The invention relates to a polishing head for a polishing machine, and more particularly, for polishing optical surfaces.
A polishing machine for polishing spherical lens surfaces is known from EP 727 280 B1. This polishing machine has an upper slide, which can move in an x-direction. A tool spindle, which is mounted for rotation around a vertical axis, is connected to this slide. The tool spindle serves to receive a surfacing tool. A workpiece spindle, connected to a further slide, is provided for receiving the respective workpiece or lens. The workpiece spindle, and the tool spindle with the surfacing tool, are arranged at a fixed distance from one another. The slide carrying these two spindles can move in the z-direction.
A polishing machine and a process for polishing optical surfaces are known from WO 97/00155. The polishing machine has a polishing head, which is provided with an elastic diaphragm. The application of force to the surface to be polished is regulated by the application of pressure to the diaphragm. In this polishing machine, it is a disadvantage that the size of the surface of the respective polishing head or diaphragm abutting the surface to be polished depends on the application of pressure. The polishing head, with the elastic diaphragm, is prestressed toward the surface to be polished by an associated spring. Hydraulic cylinders are provided in order to provide a tilting motion of the elastic diaphragm around a point situated on the rotation axis in the region of the flexible diaphragm. The application of force to the surface to be polished is detected by associated sensors, strain gages and solenoids.
In the process known from this publication, the polishing of the optical surface is controlled in dependence on the rotational speed of the polishing head, and the pressing force acting on the surface to be polished is controlled by means of the application of pressure.